Cilia, simple nerve cells in marine plankton, regulate swimming depth by their movements in much the same way that muscles in bigger animals do. When the cilia move fast, the marine plankton ascend. When the cilia stop moving, they descend. These plankton are annelid plankton, larvae from sea stars, snail, and sea shells. Many larger marine mammals depend on these tiny microscopic creatures for survival.
Max Planckand other researchers at his Institute for Developmental Biology and Thomas Munch at the Centre for Integrative Neuroscience in Tubingen studied these abundant and little understood creatures.
Neuropeptides are protein substances that control the movements of the cilia. They act as hormones and regulate target cells. When the researchers sent the substance to the cilia, it caused the plankton to move upward or at different angles. They found elevendifferent neuropeptides associates with each part of the nerve cells. The eleven α-amides include RYa, FVMa, DLa, FMRFa, FVa, LYa, YFa, and FLa; “a”, “amide”. Other precursors give rise to peptides with a carboxyl terminus (L11, SPY, and WLD).
The team tested the plankton with video microscopy and used a 25 centimeter high tube to see how the creatures swam under different conditions. Their controls initially swam in a right-handed circular and then a downward direction. The untreated larvae swam in a balanced way, unlike the controls. The RYa, FVMa, Ala substitutions did not cause the cilia to change course. This, the researchers termed washout. All the other neuropeptides did ascend or stop, though. The FLa and WLD neuropeptides slowed the movement of the cilia and even caused the plankton to descend.
Now that, scientists have found how they move, they wish to discover other aspects like how water pressure, salinity, and temperature affects their movements.
To survive in the changing marine environment, the plankton need to adjust for different aspects of the ocean like temperature, amount of phytoplankton, and light intensity. The above factors determine how fast the plankton will grow, the amount of UV damage, and the lifespan of the larva and how much it gets to eat.
Due to this understanding of cilia and neuropeptides, valuable information on how they can help in other marine biology and ecology studies. Plankton are the tiniest living forms, and knowing how they move, scientists can now find ways to protect and preserve them. They also assume that these proteins play a part in how the nervous system of other animals performs.
